Text Fx addon doesn't work
Add-ons usually give you an information where they are to find/use from. Most are in the right hand Sidebar opened with N.

Here the Text FX:


Location: "View3D > Tools" refers to the default Sidebar, as mentioned above.
The Add-on gives you the option to "add a text", which depending on the type/function you want chosen from the drop-down menu then generates an object in the 3D-View of Blender.